In some applications, such as in parabolic trough power plants or others, thermal energy is collected in an organic heat transfer fluid (HTF) for conversion to electricity via a generator. The HTF may be a eutectic mixture of biphenyl (BP) and diphenylether (DPE). Such an HTF has a maximum operating temperature of about 393° C. Its vapor pressure at this temperature is about 10 atmospheres. At about 393° C., thermal degradation reactions generate hydrogen gas (H2).
Hydrogen gas may be undesirable. For instance, it may undesirably permeate through barriers. In addition, hydrogen gas with low partial pressure has significant thermal conductivity because of its low molecular weight and correspondingly high molecular velocity. The presence of low partial pressures of hydrogen gas in a power plant, specifically in the circulating HTF, may decrease thermal performance and corresponding electricity production.